Phylogeny, function and physiology of microbes playing important roles in carbon flow in the marine subsurface environments

在过去的几十年里，人们对海洋地下环境中的微生物群落进行了研究，估计海洋地下微生物细胞的总生物量占地球总生物量碳的0.6%。然而，这些深层生命的作用在很大程度上仍然是未知的。在这项研究中，我们首先研究了编码厌氧一氧化碳脱氢酶β亚基的cooS基因在海底环境中的多样性。通过IODP考察，从墨西哥湾、富安德富卡、南太平洋环流、南开海槽和下基塔半岛附近的海洋沉积物中提取了DNA。用PCR扩增出cooS基因片段并测序。测序结果表明，与16S rRNA基因相比，沉积物中cooS基因的多样性很小。几乎所有获得的序列都与数据库中已知的cooS基因序列不相关，在系统发育树上形成不同的簇。

In the past decades, microbial community in the marine subsurface environments have been studied, and total biomass of microbial cells in the marine subsurface was estimated to contribute to 0.6% of the total living biomass carbon on the Earth. However, roles of those deep life were still largely unknown. In this study, we first investigated diversity of cooS gene, which encodes beta subunit of anaerobic carbon monoxide dehydrogenase, in the subseafloor environments. DNA was extracted from marine sediments obtained at Gulf of Mexico, Fuan de Fuca, South Pacific Gyre, Nankai Trough, and off Shimokita peninsula by IODP expeditions. Fragment of cooS gene was amplified by PCR and sequenced. The sequencing results indicated that diversity of cooS gene in the sediments were very small comparing to 16S rRNA gene. Almost all obtained sequences were not related to the known cooS gene sequences in the database and formed distinct clusters in a phylogenetic tree.